State Department spokeswoman Victoria Nuland called the arrest “evidence of a disturbing trend of growing restrictions on the freedom of expression" during a briefing with reporters on Monday.
The Cairo embassy's Twitter feed has served as a political flashpoint before. Ahead of the September 2012 embassy attacks in Egypt, the Twitter account posted a message that seemed to apologize for anti-Muslim activity in the U.S., saying the embassy "condemn[ed] efforts to offend believers of all religions."
That led to criticism from the Romney campaign, which charged that the Obama administration sympathized with the embassy attackers thought to be protesting an anti-Muslim video, and a disavowal from the Obama administration.
"The statement by Embassy Cairo was not cleared by Washington and does not reflect the views of the United States government," an administration official said.